18 INTRODUCTION 



applied to the ''perfect" stage of the fungus, regardless of the fact that 

 names may have been given earlier to some of the other stages. Thus 

 Persoon (1801) recognized the following three species of rusts which are 

 now known to be different stages of the same rust: Aecidium herheridis 

 for the aecial stage occurring on Berberis vulgaris L.; Uredo linearis for 

 the uredial stage on small grain; and Puccinia graminis, for the telial 

 stage on the same host. Only the last name may be used for the species, 

 for it is the name of the "perfect" stage. The name Lycoperdori poculiforme 

 Jacq., given 10 or 12 years earher may not be used for two reasons: it 

 was given before the basic date 1801 and was applied to the aecial stage 

 of the rust. 



The fungi, including the Mycetozoa, which probably do not belong 

 at all in this group of organisms, may be divided as follows : 



Key to the Major Groups of Fungi 



Vegetative stage permanently naked and either flagellate or amoeboid. Encysted 

 spores produced to serve as organs of distribution or to carry the organisms 

 over unfavorable conditions. 



Subclass Mycetozoa (Chap. 2) 

 Vegetative stage for all or part of its course of development with cell walls. 



True Fungi 

 Plant one-celled and then giving rise to planocytes, or producing a coenocytic 

 mycelium. Sexual reproduction resulting in the formation of a zygospore 

 or an oospore. Class Phycomyceteae (Chaps. 3-7) 



Plant one-celled, not producing planocytes, or producing a cellular mycelium. 

 Sexual reproduction resulting in the formation of a spore fruit. 



Higher Fungi (Phylum Carpomyceteae, Chaps. 8-16) 

 Ultimate reproductive spores of the spore fruit produced internally in an 



ascus. Class Ascomyceteae (Chaps. 9-11) 



Ultimate reproductive spores of the spore fruit produced externally upon 

 a basidium or its equivalent. 



Class Basidiomyceteae (Chaps. 12-15) 

 Sexual reproduction stage not known. 



Class Fungi Imperfect! (Chap, 16) 



At the close of each chapter is a key to the families and more impor- 

 tant genera of the orders considered there. 



Literature Cited 



Allen, Ruth F.: A cytological study of heterothallism in Puccinia graminis, 



/. Agr. Research, 40(7) :585-614. Pis. 1-17. 1930. (This paper was followed 



by many others in the same field in the next six years.) 

 Ames, Lawrence M.: An hermaphroditic self-sterile but cross fertile condition 



in Pleurage anserina. Bull. Torrey Botan. Club, 59(6) :341-345. Fig. 1. 1932. 

 Andrus, C. F.: The mechanism of sex in Uromyces appendiculatus and U. vignae, 



J. Agr. Research, 42(9):559-587. Figs. 1-11. 1931. 

 DE Bary, Anton: Die Mycetozoen. Ein Beitrag zur Kenntnis der niedersten 



Thiere, Z. wiss. Zool, 10(1):88-175. Pis. 6-10. 1859. 



